My wife has a pre-Gibson Trace Elliot AH250SMX that pops through the speakers a few times when power is turned off with the power strip, but doesn't if it's shut off with the onboard switch. Plugged directly into the wall, it does the same thing if I pull the power cord. If she turns the onboard switch off and then unplugs the unit (to move off stage at a jazz concert), it will make the same pops as the unit discharges. Other than that, the amp works flawlessly. She never has to worry about needing more power Is there a bad cap in the power supply somewhere?